1. Field of the Invention
The invention relates to an arm member that is attached to a pivot member and supports a wheel of a straddle-type vehicle.
2. Description of Related Art
A straddle-type vehicle such as a motorcycle often has an arm member that rotatably supports a rear wheel. The arm member is generally formed by left and right arms to which a wheel axle is attached. A connecting (cross) member is provided between and connects the arms. The connecting member may include a plurality of members, namely, a bridging plate that connects the arms and a vertical rib that extends vertically from the bridging plate (for example, refer to JP-UM-A-5-60997, FIG. 2).
In addition, the arm member preferably is able to bend to a suitable extent when a load is applied thereto. To address this need, the shape of the arms (for example, the thickness) may be changed to adjust the rigidity of the arm member.
However, because the connecting member is formed from a plurality of members, the manufacturing process of the arm member is complicated. Changing the shape of the arms in accordance with rigidity requirements also increases manufacturing costs.